These instructions should work on both the Mac in OSX and the PC in Windows XP/Vista/7 but the screenshots are from the Mac. Make sure you've downloaded the latest version of iTunes from Apple, and you also need to install the free iBooks application.
- Download the epub file following the instructions provided elsewhere – save the file to your desktop.
- Open iTunes on the desktop.
- From the 'File' menu in iTunes, select add to library:
- Point iTunes to your Desktop and click on the downloaded file, then click the 'Choose' button:
- The new book should now appear in your library in the 'Books' section:
- Connect your iPad or iPhone, make sure in the 'Books' tab the book is selected (ticked) and do a sync:
- To read the book, open iBooks on your device.